8 Scientific Benefits of Napping

Even on the best of days, life can be exhausting. If you find your energy flagging in the middle of the day, you might like to know that 34 percent of Americans nap. Napping is a healthy way to restore the deficits of sleep deprivation. Whether you bow down to the ritual of a mid-afternoon siesta or never stop to snooze, you may think twice about the power of napping after reading about these eight benefits.

1. NAPPING CAN BOOST YOUR IMMUNE SYSTEM.

Sleep deprivation—particularly repeated, chronic lack of sleep—takes a toll on your neuroendocrine and immune functions by increasing inflammatory molecules known as cytokines, as well as stress hormones like cortisol and norepinephrine. A 2015 study in the Journal of Clinical Endocrinology & Metabolism took 11 healthy young men and restricted them to a night of only two hours of sleep. Blood and urine tests measured higher cytokines and levels of norepinephrine in both groups after sleep deprivation. The following day, one group was given two half-hour naps, while the control group did not have any naps. Blood and urine samples of those who napped showed that their cytokines and norepinephrine levels had returned to normal, as though they had never lost a night of sleep.

2. A NAP CAN IMPROVE NIGHT ALERTNESS.

For people who work at night, or through the night, several studies have shown that naps from between 30 minutes and four hours long that are taken in advance of the shift—what's known as a "prophylactic nap"—improve performance and alertness. These naps can also improve nighttime driving alertness on the way home from the shift. However, most of these studies also include the administration of caffeine, which likely contributed. Yet a 1995 study in Sleep, which compared naps and caffeine, found that "naps, in general, provided longer and less graded changes in performance, mood and alertness than did caffeine, which displayed peak effectiveness and loss of effect within about six hours."

Surgeons must often perform continuous surgery for hours longer than the average person would ever have to persist at a task. A 1994 study in the journal Ergonomics found that naps were indeed effective at keeping surgeons who had to remain awake for 24 hours alert, but only when caffeine was administered, too. Neither naps or caffeine alone were sufficient.

4. TO IMPROVE DAYTIME ALERTNESS, TAKE FREQUENT NAPS.

Daytime napping also appears to improve mental alertness and performance, according to a number of laboratory studies. However, researchers found that shorter naps were more effective than longer ones. The most effective time of them all was 10 minutes, which produced the best outcomes in all sleep measures including "subjective sleepiness, fatigue, vigor, and cognitive performance." A 30-minute nap could produce the same effects but brought about "a period of impaired alertness."

5. NAPS HELP YOU LEARN NEW SKILLS.

If you want to get better at learning a new skill, you might want to take more frequent naps. A 2006 study in Biological Physiology broke participants into two groups: those who napped frequently and those who napped sporadically. Each group was given a nap before a reading task. Habitual nappers—people who reported napping frequently—did better on the reading and retention task. Researchers determined that the brains of habitual nappers consolidated motor learning better, which is part of the process of learning a new skill.

6. IMPROVE YOUR PHYSICAL STAMINA WITH NAPPING.

It turns out that napping is not only just good for mental processes, but has a positive impact on physical stamina and performance as well. A 2007 study in the Journal of Sports Sciences put 10 healthy men through a series of sprints before and after a 30-minute, post-lunch nap. Sprint times improved after the naps, suggesting to the researchers that a post-lunch nap "improves alertness and aspects of mental and physical performance following partial sleep loss." They suggest that napping may be an important part of the regimens of athletes who are undergoing restricted sleep during training or competition.

7. NAP TO IMPROVE YOUR MEMORY.

One of the many functions of regular nighttime sleep is to consolidate memory. A 2010 study in Neurobiology of Learning and Memory set out to see whether daytime naps also improve memory processes, particularly associative memory (the ability to make connections between unrelated objects). Thirty-one healthy participants were given a learning task at 12 p.m. to memorize two sets of face-object photograph pairs. The objects in each pair occurred in both sets but were paired with different faces. Participants were broken into two groups: those who had a 90-minute daytime nap or those who did not. At 4:30 p.m., participants who napped showed notably better retention of associative memory.

8. A 90-MINUTE NAP IS AS GOOD AS A FULL NIGHT’S SLEEP FOR PERCEPTUAL LEARNING.

Previous research demonstrated that people perform better on a visual texture-distinguishing task after a night of sleep than they do immediately after learning it. A 2003 study in Nature Neuroscience found that people performed just as well on the test after a 60- to 90-minute nap as they did after a full night of slumber.

"What's amazing is that in a 90-minute nap, you can get the same [learning] benefits as an eight-hour sleep period," lead author Sarah Mednick said in an interview with the American Psychological Association. "The nap is having an additive benefit on top of a good night of sleep."

L’Oréal’s New Wearable Sensor Keeps Track of Your Daily UV Exposure

Anyone who has ever suffered a sunburn knows that too much exposure to UV radiation is bad for your skin. But in the moment, it can be hard to tell when you’ve gotten too much sun—especially during the winter, when you might not think you need sunscreen. (In reality, snow reflects up to 80 percent of the sun’s UV light, so you may end up getting hit with the same rays twice.) A new wearable sensor spotted by Wired aims to make understanding your sun exposure a whole lot easier.

L'Oréal’s new La Roche-Posay My Skin Track UV sensor pairs with a smartphone app to alert users when they’ve had high levels of UV exposure. Developed by L'Oréal’s Tech Incubator in collaboration with Northwestern University engineering professor John Rogers and Swiss designer Yves Béhar, the sensor measures UVA rays (which are associated with skin aging and skin cancer) and uses an algorithm to calculate UVB exposure (which is associated with sunburn and skin cancer).

L'Oréal USA

At only half an inch tall and 1.3 inches long, the waterproof sensor is designed to be discreetly attached to your clothes, watchband, or sunglasses. The sensor's LED detector measures UV rays as sunlight passes through a small window in the device, then transfers the data to your phone via a near-field communication (the same technology in some hotel key cards). It stores the photons from the UV rays in a capacitor, eliminating the need for a battery.

Based on this data, the My Skin Track app can tell you how close you're getting to the maximum limit of UV exposure doctors recommend per day. It also provides updates about the air quality, pollen count, and humidity wherever you are at any given moment. Based on this information, as well as data about your specific skin type and skin tone, the app's Skin Advice feature will provide customized tips for keeping your skin healthy. It also recommends specific products—La Roche-Posay items can be bought directly through the app, should you desire.

The sensors are exclusively available through Apple stores. You can order one online for $59.95.

Massive Salmonella Outbreak Linked to Raw Turkey Just Days Before Thanksgiving

The U.S. has been in the midst of a salmonella outbreak for more than a year, with the bacteria contaminating everything from cereal to snack foods as well as raw poultry. Now health experts warn that your Thanksgiving dinner may put you at risk for infection. As ABC reports, salmonella has been traced back to a number of turkey products, and Consumer Reports is urging the USDA to name the compromised brands ahead of the holiday.

The drug-resistant strain of salmonella linked to the recent outbreak has been detected in samples taken from live turkeys, raw turkey products, and turkey pet food, according to the Centers for Disease Control and Prevention (CDC). Since November 5, 2017, 164 people in 35 states have contracted the infection from a variety of products.

While many of the items linked to the salmonella outbreak have been pulled from shelves, the potentially contaminated turkey brands have yet to be identified. In a news release, Consumer Reports urged the USDA to release this information in time for consumers to do their Thanksgiving shopping.

"The USDA should immediately make public which turkey producers, suppliers, and brands are involved in this outbreak—especially with Thanksgiving right around the corner," Jean Halloran, director of food policy initiatives for Consumers Union (the policy department of Consumer Reports), said in a statement. "This information could save lives and help ensure consumers take the precautions needed to prevent anyone in their home from getting sick."

Even if specific brands aren't flagged before November 22, the CDC isn't telling consumers to skip the turkey altogether. Instead, home cooks are encouraged to practice the same safety precautions they normally would when preparing poultry. To avoid salmonella poisoning, start with a clean work area and utensils and wash your hands and counter thoroughly before and after preparing the bird. But skip washing the bird itself, as this can actually do more to spread around harmful pathogens.

Cook your turkey until the meatiest part reaches an internal temperature of 165°F. And if you're looking for a way to make sure the juiciest parts of the turkey cook through without drying out your white meat, consider cooking the parts separately.